1. Field of the Invention
The present invention generally relates to a sense amplifier of a nonvolatile ferroelectric memory device, and more specifically, to a ferroelectric sense amplifier for effectively sensing and amplifying cell data having a small voltage difference applied to a main bit line, thereby improving operation characteristics in a low voltage.
2. Description of the Prior Art
Generally, a ferroelectric random access memory (hereinafter referred to as ‘FeRAM’) has a data processing speed as fast as a Dynamic Random Access Memory (hereinafter referred to as ‘DRAM’) and conserves data even after the power is turned off.
The FeRAM having structures similar to the DRAM includes the capacitors made of a ferroelectric substance so that it utilizes the characteristic of a high residual polarization of the ferroelectric substance in which data is not deleted even after an electric field is eliminated.
The technical contents on the above FeRAM are disclosed in Korean Patent Application No. 1999-14400 or a patent by the same inventor of the present invention. Therefore, the basic structure and the operation on the FeRAM are not described herein.
However, as the operating voltage of the FeRAM becomes lower and its power consumption also becomes lower, a cell sensing voltage is reduced, which results in difficulty in embodiment of rapid operation speed. As a result, a change is required in a method for sensing data. Additionally, as the structure of cell arrays becomes diverse, it also requires diverse methods for sensing data.